Dental syringe.



F. L. PLATT, G. N. HEIN &, R. R. IMPBY. DENTAL SYRINGE.

APPLICATION FILED MAILZB. 1914.

1,1 17,701. Patented Nov. 17, 1914.

WITNESSES:

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FRANK L. PLATED, GEORGE N. HEIN, AND ROBERT R. IIsTPEY, OF SAN FRANCISCO, CALIFORNIA.

DENTAL SYBINGE.

T 0 all whom it may concern Be it known that we, FRANK L. PLATT, GEORGE N. HEIN, and ROBERT E. IMPEY, citizens of the United States, residing in the city and county of San Francisco and State of California, have invented certain new and useful Improvements in Dental Syringes, of which the following is a specification.

The present invention relates to improvements in syringes and more particularly to that type of syringe employed by dentists in injecting a medicament into the gums when working on the mouth of a patient.

The invention has for its principal objects to provide a syringe which is capable of being taken apart and thoroughly sterilized after being used, one which is free from the materials usually affected by sterilization,

. one which is constructed in such a manner as to be proof against leakage when in operation, and one in which the packing material for the joints of the several sections is such as to necessitate few renewals during the life of the syringe, and which is capable of being readily sterilized without injury to the same.

With the above mentioned and other objects in view, the invention consists in the novel construction and combination of parts hereinafter described, illustrated in the accompanying drawings, and pointed out in the appended claim; it being understood that various changes in the form, proportion, size, and minor details of construction within the scope of the claims, may be resorted to without departing from the spirit or sacrificing any of the advantages of the invention.

To more fully comprehend the invention, reference is directed to the accompanying sheet of drawings, wherein Figure 1 is a view in elevation of our improved syringe, disclosing the barrel, the plunger and the needle. Fig. 2 is a longitudinal sectional view, disclosing the manner of assembling the several parts of our invention. Fig. 3 is an enlarged longitudinal sectional view of the end cap and needle, disclosing the packing joints between connected members.

Referring more particularly to the drawings, the reference numeral 1 designates a suitable metallic barrel formed with a longitudinally disposed tubular bore 2 extending the full length thereof, and said barrel Serial No. 827,877.

is provided adjacent one end with oppositely disposed laterally extending finger pieces 3. Slidably mounted in said bore 2 is a metallic plunger 4; which is of a diameter to when the fingers engage the finger pieces 3.

One end of said bore is enlarged, as at 6, and the base of said enlargement is beveled as at 7. A suitable packing 8, preferably in the form of a rubber washer cut from a single blank and surrounding said plunger, is seated in said enlargement and said washer is acted on by the lower beveled edge 9 of a metallic tubular follower 10, which is forced into engagement with said packing by an end cap 11, which threads over the end of the barrel 1 and through which the plunger 4: operates, and said end cap is inwardly beveled on its outer surface toward its center, as at 12, to facilitate in the insertion and guiding of the plunger into the bore. A suitable union 13 is threaded over the opposite end of said barrel by a left hand threaded connection 13, as in Fig. 1, and said union is provided with a fluid channel or bore 11 of a diameter considerably smaller than the bore 2 and is formed with an annular seat 15 surrounding said bore 1 1 for receiving the lower end of said barrel, and mounted in said seat is a suitable metallic packing 16 preferably of block tin. The outer end of said union 13 carries a suitable right hand threaded stud 17 over which is threaded the collar 18 carrying the tubular tapered needle 19. Around the threaded stud 17 is also formed an annular seat 20 and in the same is contained a suitable metallic packing 21, preferably of block tin, and the contracted portion 22 of said collar 18 is adapted to seat against said metallic packing and provide a fluid tight joint between the two parts.

It will be apparent that we have provided a structure which is capable of being taken apart and sterilized after each time the same is used, and that by constructing the joints between the barrel and the coupling, and the coupling and the needle with a metallic packing, preferably of block tin, that the parts may be separated and assembled without wearing the packing and may also be sterilized without affecting the packing.

By providing the packing 8 surrounding Patented Nov. 17, 1914. 7

the plunger and positioning the same in a recess having a beveled seat, we are enabled by forcing the follower 10 downwardly thereon to force the packing tightly around the plunger 4: and maintain a fluid tight o1nt.

By providing the left hand thread connection between the barrel and the coupling, and a right hand thread between the coupling and the needle collar, it will be apparent that a strain will be placed on the coupling in a direction to screw the same tightly onto the barrel at such time as the needle is tightened on the coupling and a strain will be placed on the coupling to unscrew the same from the barrel at such time as the needle is unscrewed from the coupling.

Having thus described our invention what we claim as new and desire to protect by Letters Patent is In a syringe of the character described, the same comprising a metallic barrel formed with a bore extending longitudinally thereof and provided with finger grips on its outer surface adjacent one end, said barrel being formed on one end with an internal enlargement having a downwardly beveled bottom wall and said barrel being externally threaded at opposite ends, a coupling formed with a bore to communicate with said first mentioned bore and provided. with an annular seat surrounding said bore, said coupling threaded internally at one end and adapted for connection on one end of said barrel, a metallic packing in said annular seat, an extended stud surrounding the outer end of said bore in said coupling and threaded externally, a hypodermic needle base threaded internally for c0nneotion with said stud, an annular channel surrounding said stud, a metallic packing in said channel for engagement by said needle base, a plunger mounted in the bore of said barrel and formed at one end with a hand grip, a removable packing seated in the in ternal enlargement of said barrel, a follower surrounding said plunger and projecting into said internal enlargement to cooperate with said last mentioned packing, and a cap threaded on said barrel for actuating said follower.

In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses.

FRANK L. PLATT. GEORGE N. HEIN. ROBERT R. IMPEY.

Witnesses HARRY A. TOTTEN, D. B. RICHARDS.

- Copies of this patent may be obtained for rive cents each, by addressing the Commissioner of Batents,

Washington, D. C. 

